The common walnut and the black walnut and its allies, are important for their attractive timber, which is hard, dense, tight-grained and polishes to a very smooth finish. The colour ranges from creamy white in the sapwood to a dark chocolate colour in the heartwood. When kiln-dried, walnut wood tends toward a dull brown colour, but when air-dried can become a rich purplish-brown. Because of its colour, hardness and grain, it is a prized furniture and carving wood. Walnut burls (or ‘burrs’ in Europe) are commonly used to create bowls and other turned pieces. Veneer sliced from walnut burl is one of the most valuable and highly prized by cabinet makers and prestige car manufacturers. Walnut wood has been the timber of choice for gun makers for centuries, including the Gewehr 98 and Lee Enfield rifles of the First World War. It remains one the most popular choices for rifle and shotgun stocks, and is generally considered to be the premium â€“ as well as the most traditional â€“ wood for gun stocks, due to its resilience to compression along the grain. Walnut is also used in lutherie, i.e. making stringed musical instruments. The wood of the butternut and related Asian species is of much lower value, softer, coarser, less strong and heavy, and paler in colour.
In North America, forestry research has been undertaken mostly on J. nigra, aiming to improve the quality of planting stock and markets. In some areas of the US, black walnut is the most valuable commercial timber species. The Walnut Council is the key body linking growers with scientists. In Europe, various EU-led scientific programs have studied walnut growing for timber.